GENERAL
Stored Setups: Stores front panel settings and nine addi-
tional front-panel setups in a non-volatile RAM. A system
menu allows saving and recalling of instrument setups.
Whenever the instrument is turned on, control settings come
on at the same functions and values existing when the instru-
ment was turned off.
Memory Sequencing Input: Accepts a TTL low-level sig-
nal to sequence through nine stored setups. AUX I/O con-
nector, rear panel.
Self-Test: Instrument self-test is performed when Selftest
soft-key is selected. If an error is detected, an error message
is displayed in a window on the LCD identifying the probable
cause and remedy.
Secure Mode: Disables all frequency and power level dis-
plays. Stored setups saved in secure mode remain secured
when recalled. Selectable from a system menu.
Parameter Entry: Instrument-controlled parameters can be
entered in three ways—keypad, rotary data knob, or the
∧
and
∨
touch pads of the cursor-control key.
The keypad is used to enter new parameter values; the
rotary data knob and the cursor-control key are used to
edit existing parameter values. The < and > touch pads of
the cursor-control key move the cursor left and right one
digit under the open parameter. The rotary data knob or
the
∧
and
∨
touch pads will increment or decrement the
digit position over the cursor.
Controlled parameters are frequency, power level, sweep
time, dwell time, and number of steps.
Keypad entries are terminated by pressing the appropriate
unit key (GHz/Sec/dBm, MHz/ms/dB, kHz/
µ
s/STEPS, or
Hz/ns/ADRS). Edits are terminated by exiting the edit
menu.
Master Reset: Returns all instrument parameters to prede-
fined default states or values. Any pending GPIB I/O is
aborted. Selectable from the system menu.
Master/Slave Operation: Allows two 681XXA output sig-
nals to be swept with a user-selected frequency offset. One
681XXA unit controls the other via AUX I/O connection.
Warm Up Time (Standard Time Base):
From Standby:
30 minutes.
From Cold Start (0
°
C):
120 hours to achieve <1 x 10
–7
per day frequency stability.
Warm Up Time (Option 16 Time Base):
From Standby:
30 minutes
From Cold Start (0
°
C):
72 hours to achieve <5 x 10
–10
per day frequency stability.
Power:
115 Vac
±
20% or 230 Vac
±
20%, 48–440 Hz, 400 VA
maximum
Standby: With ac line power connected, unit is placed in
standby when front panel power switch is released from the
OPERATE position.
Weight: 23 kg (50 lb) maximum
Dimensions:
133 H x 429 W x 597 D mm
(5.25 H x 16.875 W x 23.5 D in)
RF Output Connector:
Type K female.
ENVIRONMENTAL
Storage Temperature Range: –40
°
C to +75
°
C.
Operating Temperature Range: 0
°
C to +50
°
C.
Relative Humidity: 5% to 95% at 40
°
C.
Altitude: 4,600 meters, 15,000 ft, 17.3" Hg.
EMI: Meets the conducted and radiated emission require-
ments of MIL-STD-461B CEO2, CEO3, CEO4, and REO2.
PERFORMANCE
SPECIFICATIONS
681XXA OM
B-5
